Design, Synthesis, Docking Study and Biological Evaluation of 4-Hydroxy-2H-benzo[e][1,2]thiazine-3-carboxamide 1,1-dioxide Derivatives as Anti-HIV Agents

A novel series of benzothiazine-3-carboxamide 1,1-dioxide derivatives by modifying the piroxicam scaffold was designed, synthesized, and evaluated as anti-HIV agents. The 1,2-benzothiazine-3-carboxamide 1,1-dioxide scaffold consists of hydroxy and carboxamide groups as a chelating motif to form an interaction with Mg2+ ions within the integrase active site as a target. Most of the compounds displayed encouraging anti-HIV activity in a cell-based assay. Among them, compounds 13d, 13l and 13m were the most potent with EC50 values ranging from 20-25 mM and SI > 26. Docking study of compounds in integrase active site proposed that the mechanism of action of compounds might be through Mg2+ chelation within integrase active site. The lack of severe cytotoxicity and favorable anti-HIV activity of benzothiazine-3-carboxamide 1,1-dioxide derivatives support further modifications to improve the potency.